Hello.
The actor has 1 UStaticMeshComponent component.
In Runtime or in the editor (OnConstruction), I create an additional component:
UStaticMeshComponent* comp = NewObject<UStaticMeshComponent>(this);
comp->AttachToComponent(Root, FAttachmentTransformRules::KeepRelativeTransform);
comp->RegisterComponent();
How to clone all the properties of a component to a second component (Static Mesh, Materials, settings in the Render Tab)?
UPD:
problem solved: DuplicateObject
UStaticMeshComponent * comp2 = DuplicateObject <UStaticMeshComponent> (comp, this);